U.S. senators expressed concern on Wednesday about a plan to overhaul the U.S. healthcare system, fearing a rush to consider the major legislation as Republican leaders prepare to unveil it.

The healthcare bill will be released to the Republican Senate Conference on Thursday at 9:30 a.m. EDT (1330 GMT) and posted online, Senators John Barrasso of Wyoming and Bob Corker of Tennessee told reporters in the Capitol on Wednesday.(Reuters)

U.S. senators expressed concern on Wednesday about a plan to overhaul the U.S. healthcare system, fearing a rush to consider the major legislation as Republican leaders prepare to unveil it. The healthcare bill will be released to the Republican Senate Conference on Thursday at 9:30 a.m. EDT (1330 GMT) and posted online, Senators John Barrasso of Wyoming and Bob Corker of Tennessee told reporters in the Capitol on Wednesday. A vote could come as soon as next week, several senators said. “There is an urgency to get this done because of the continued collapse of the Obama health care law,” Barrasso, a member of the Senate Republican leadership, told CNN. “People across the country are suffering pain and the pain is getting worse as insurance companies are pulling out.”

Legislators from both sides of the aisle have expressed their displeasure and Democrats hoping to block the measure need at least two Republicans to defect. Senate Republicans have been working behind closed doors for weeks on legislation aimed at repealing and replacing major portions of the Affordable Care Act, former Democratic President Barack Obama’s signature healthcare law, popularly known as Obamacare. Senate Majority Leader Mitch McConnell, defending the closed-door sessions, has said all Senate Republicans have had a chance to participate in meetings on the bill, and that Democrats are not interested in discussing Obamacare repeal.

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The Senate proposal is expected to cut back the expansion of Medicaid, the government program for the poor, and reduce subsidies to people buying private insurance. But negotiations have been plagued from the start by tensions between moderates and conservatives. In addition, a growing number of Republicans are frustrated with the process, saying they apparently will have just a few days to study the draft before being forced to vote on a major piece of legislation.

Republican Senator Ron Johnson of Wisconsin said he wanted to read the bill and discuss it with constituents before he votes. “I’d find it hard to believe we’ll have enough time,” he said, adding that if he doesn’t get enough information “I won’t be voting yes.” Senator Susan Collins, a moderate Republican from Maine, said she wants to read an assessment by the nonpartisan Congressional Budget Office (CBO) on its impact on cost and insurance coverage before making her decision.

“The first concern is how many people will lose coverage and what do the demographics of that group look like,” she said. An estimated 23 million people could lose their healthcare under a similar plan narrowly passed last month by the House of Representatives, according to CBO. Conservative Senator Rand Paul of Kentucky said he had not yet seen the Senate bill. But he promised voters he would seek full repeal of Obamacare, and “everything I hear (about the Senate draft) sounds like Obamacare light.” Given the opposition of all Senate Democrats to repealing Obamacare, Republican leaders will need the support of at least 50 of the chamber’s 52 Republicans to ensure passage.